This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from my application METHOD AND APPARATUS FOR IMPLEMENTING ANSI TCAP IN MOBILE COMMUNICATION NETWORK SYSTEM filed with the Korean Industrial Property Office on Nov. 20, 1999 and there duly assigned Serial No. 51745/1999.
1. Field of the Invention
The present invention relates to a wet type electrophotographic color printer, and more particularly to a wax coating device for a wet type electrophotographic color printer for coating wax on printed matter, thereby protecting images printed on the printed matter.
2. Description of the Prior Art
Generally, a wet type electrophotographic color printer prints a desired image by forming the electrostatic latent image through the processes of: radiating a laser beam onto a photosensitive medium, such as a photosensitive belt; developing the electrostatic latent image formed on the photosensitive medium with a developing solution composed of a solid toner of a certain color and a liquid carrier as a solvent; and transferring the developed form to printed matter.
Generally, in such printers, a liquid condensed ink is used, and that causes newly printed sheets to be sticky. This presents a problem when such sheets are stacked on top of each other. In order to correct the latter problem, a coating of wax is often applied to paper after completion of the printing operation, such wax coating being selectively carried out only for certain type of print media. However, in such printers which carry out the wax coating procedure, there is a further problem in that print media which are not to be coated often can be partially smeared with wax as a result of undesired contact between the print media and a wax coating roller of the printer. There is a need in the prior art for a printer and wax coating device which preclude this undesirable disadvantage.
The present invention has been developed to overcome the above-mentioned problems of the prior art. Accordingly, it is an object of the present invention to provide a wax coating device for a wet type electrophotographic color printer capable of selectively performing a wax coating operation, i.e., capable of performing a complete wax coating operation on printed matter which requires a wax coating, and capable of preventing the smearing of wax on printed matter which is not supposed to be wax-coated, such as an OHP film, etc. In accordance with the present invention, printed matter is prevented from coming into contact with the coating roller.
The above object is accomplished by a wax coating device for a wet type electrophotographic color printer according to the present invention, which includes: a frame mounted on a printer body; a wax tank fixed on the frame; a coating roller rotatably disposed so as to be partially immersed in wax contained in the wax tank; a pressing roller in tight contact with the coating roller so as to press printed matter passing between the coating roller and the pressing roller against the coating roller; pressing roller spacing means for permitting the printed matter to pass between the pressing and coating rollers without touching the pressing and coating rollers by selectively spacing the pressing roller away from the coating roller; and coating prevention means for preventing the printed matter from making contact with the coating roller by being advanced/withdrawn between/from the pressing and coating rollers in accordance with the movement of the pressing roller spacing means when the printed matter passes between the pressing and coating rollers.
The pressing roller spacing means includes: a pair of pressing roller brackets rotatably disposed on the frame by a pin, each having one end on which the pressing roller is rotatably disposed and another end on which an operational pin is provided; a pair of cam gears rotatably disposed on the frame by means of a shaft, each having cams formed on an outer surface thereof so as to be in contact with the operational pin of the pressing roller brackets, for rotating the pressing roller brackets in such a direction as to enable the pressing roller to be spaced apart from the coating roller; driving means for rotatably driving the cam gears; and a pair of pressing springs disposed between the pressing roller brackets and the wax tank for elastically biasing the pressing roller brackets in such a direction as to enable the pressing roller to be tightly pressed against the coating roller.
The coating prevention means includes: a pair of cam grooves, each formed on an inner surface of a respective cam gear and each having a shape such that a distance from a center of the cam gear to the cam groove progressively increases; a cover disposed for linear movement on a supporting member which is fixed to the frame, the cover having one end on which a pair of operational protrusions is formed so as to be inserted in the cam grooves, the cover covering the coating roller by being advanced/withdrawn between/from the pressing and coating rollers in accordance with the rotational movement of the cam gears; and guiding means for guiding movement of the cover.
In a wax coating device according to the present invention, when there is no need for wax-coating of the printed matter, the pressing roller is spaced from the coating roller while the cover is advanced, thus blocking the coating roller from the pressing roller and the printed matter. Accordingly, when printed matter which is not supposed to be wax-coated passes between the pressing and coating rollers, undesired contact of the printed matter with the coating roller is prevented, and the printed matter is not smeared with wax.